School Starting times?

Thank you all for your excellent advice on new classroom setups. We'll see
what happens....

Another question:
My school is k-3 (ages 5-8). Other schools in the district with older
students start their days much earlier than ours does. My experience,
however, is that younger children are much more ready to learn early in the
day, rather than older children.
I am working with another teacher to convince the district that primary
schools need to begin instruction early, like 8am, rather than our current
9am. We need documentation to back this up, however. Any suggestions?